相比传统的点扫描激光雷达，基于距离选通和增益调制测距原理的面阵成像激光雷达，具有测距速度快的优点，但同时会引起单帧图像信噪比降低。根据成像激光雷达的原理，建立了其在散粒噪声影响下的测距精度模型，基于该精度模型和机载面阵激光雷达成像的特点，提出了一种应用灰度图像配准叠加提高测距精度的方法。对飞机姿态、光源均匀性、叠加帧数等因素在采用该方法时是否对测距精度有影响进行了分析。分析结果表明，图像完全匹配后，飞机姿态对测距精度没有影响，光源均匀性优于40%时对测距精度影响可以忽略，一定叠加帧数内时灰度叠加不会影响目标之间的相对距离。进行了地面动态实验和机载航拍实验，并将此方法应用于图像的校正，实验结果验证了该方法的有效性。

Compared with traditional point-scanning laser radar, the imaging laser radar based on range gating and gain-modulation ranging principles has faster ranging speed, but at the same time, signal noise ratio (SNR) of single-frame image is lower. According to principles of imaging laser radar, the ranging accuracy model under the influence of shot noise is built. Based on the model and the characteristics of airborne imaging laser radar, a new method which employs the techniques of gray image registration and superposition to improve ranging accuracy is put forward. Then the factors, such as the flight attitude, light uniformity and superposition frame number that influence the application of gray registration and superposition, are analyzed theoretically. The results show that flight attitude has no effect on the method and the light uniformity′s effect is small when the uniformity is better than 40%. There will not be other errors between the targets when superposition frame number is within a certain range. A ground of dynamic experiments and aerial experiment are conducted to verify the validity of the method.